PRECURSOR FOR Nb3Sn SINGLE-CORE SUPERCONDUCTING WIRE RODS AND METHOD FOR PRODUCING SAME, Nb3Sn SINGLE-CORE SUPERCONDUCTING WIRE ROD, PRECURSOR FOR Nb3Sn MULTICORE SUPERCONDUCTING WIRE RODS AND METHOD FOR PRODUCING SAME, AND Nb3Sn MULTICORE SUPERCONDUCTING WIRE ROD

摘要

A precursor (1) for Nb₃Sn single-core superconducting wire rods according to the present invention is provided with: an Sn-based wire rod (10); a first Cu-based tube (20) that covers the outer circumferential surface of the Sn-based wire rod; an Nb-based tube (30) that covers the outer surface of the first Cu-based tube; and a second Cu-based tube (40) that covers the outer surface of the Nb-based tube. The Sn-based wire rod comprises a matrix phase (11) and one or more hard phases (12) that are harder than the matrix phase; and in a cross-section of the precursor for Nb₃Sn single-core superconducting wire rods, said cross-section being parallel to the longitudinal direction of the precursor, the maximum length of each of the hard phases in the width direction, which is perpendicular to the above-described longitudinal direction, is 50% or less of the minimum length of the Sn-based wire rod in the above-described width direction and/or not more than the minimum thickness of the Nb-based tube in the above-described width direction.